Transmitting apparatus in teleprinters



Sept. 20, 1938. R. D. SALMON El AL TRANSMITTING APPARATUS IN TELEPRINTERS Filed Dec. 10, 1935 u 7 //VVE/V7URS EA. THOMAS Arra/wyr Patented Sept. 20, 1938 UNITED STATES PATENT OFFICE TRANSMITTING APPARATUS IN TELE- PRINTERS land 7 Application December 10, 1935, Serial No. 53,702

In Great Britain February 22, 1935 4 Claims.

This invention relates to telegraph apparatus and more particularly to answer back devices. Such a device consists of a sleeve carrying a plurality of sets of cams, each set representing a 5 character, which forms part of a teleprinter and is adapted to be automatically released on the receipt of a distinctive signal to cause the transmission of the characters represented by the sets of cams. These characters indicate the identity 10 of the station at which the teleprinter is located,

usually a telephone exchange and number.

In such devices the cams representing the characters to be transmitted usually act directly upon I a set of combination bars to control the transmission of the characters, as described in British Patent No. 351,018. If it be desired to transmit a considerable number of characters it has hitherto been necessary to make the sleeve carrying the cams of large diameter.

The present invention has for its object to enable cams representing a considerable number of characters to be placed on a sleeve of comparatively small diameter.

According to one feature of the present invention we provide telegraph apparatusof the kind referred to in which the sets of cams representing characters act upon the transmitting contact tongue through the medium of a series of pivoted levers brought into contact with said cams to be positioned thereby and out of contact therewith for each character to be transmitted.

The cams representing the character may, by this means be made of small size, since they do not act on the levers to cause positive movement thereof, but the levers merely feel the nature of the cams against which they are moved.

According to another feature of the invention, telegraph apparatus of the kind referred to comprises a pair of parallel shafts, one of said shafts 40 being automatically released for rotation on the receipt of a distinctive signal and driving the other of said shafts, which carries the said sleeve, in such a manner that the first mentioned shaft rotates a large number of revolutions for one 45 revolution of the second mentioned shaft, and cam means on said second mentioned shaft for maintaining the first mentioned shaft in rotation until the first mentioned shaft has completed one revolution.

In this way the diameter of the sleeve may be made small, since the main cam-controlled operations are performed by the shaft that rotates at the faster speed, and the cams that serve to carry out the various operations are less steeply cut and therefore subject to less shock and Wear than if they were upon the slowly moved shaft.

One embodiment of the invention will be described with reference to the accompanying drawing in which V Fig. 1 is a cross section of the device, and

Figs. 2, 3, 4 and 5 are sectional elevations taken on the lines A, A, B, B, C, C, D, D, respectively. For the sake of clearness the various levers shown in Figs. 2 to 5 have been omitted from Fig. 1. 7

Referring to Fig. 1, 25 is a spindle carrying a sleeve 26 upon which are mounted three cams 28, 29 and 30, a gear wheel 27 and a sleeve 33 carrying cams 32. Gear wheel 21 is driven via gear wheels 23 and 24 fromgear wheel 22 mounted on a second spindle 36 driven from a friction clutch l9. Spindle 36 carries a detent I and three cams i8, 2!] and 2|. Lever II (Fig. 4) normally engages with detent HJ so as to arrest spindle 35. The upwardly extending portion of lever ll engages with cam 28. Lever 6 (Fig, 3) is controlled by cam 30 and also by cam 2i. The lower portion of lever 6 extends across the five selector levers 4, the upper'ends of which cooperate with cams 32 on sleeve 33. At their lower end the levers 4 are acted on by springs 2 tending to move them into contact with the cams, and they are also'adapted to engage with projections on transfer bars 3. Lever is controlled by cam 36 and also by cam 20, and is acted upon at its lower end by spring 1. It also carries at its lower end a pin engaging with another'projec'tion on transfer bars 3.

The gear ratio between spindle 36 and the sleeve 26 is such that the spindle 36 makes a large fraction of a revolution, say a quarter of a revolution, whilst sleeve 26 rotates an amount equal to the pitch between the rows of cams on the sleeve 33; in the present case provision is made for 24 rows on the sleeve. A spindle 36 also carries a. cam 18 co-operating with a lever 16 engaging with a bar ll. The bar I! is adaptedlto release the clutch of the start stop transmitter, and bars 3 are adapted to control the signals sent out from this transmitter.

Lever II also carries an extension engaging with lever 53 which is under the control of the receiving mechanism, and an extension 9 engaging with a bar 8 adapted to prevent the depression of any key on the keyboard.

The operation of the device is as follows:-

Upon the receipt of the answer back signal on the receiving mechanism the lever I3 is operated, so causing the lever I I to rotate in an anticlockwise direction, thus releasing detent l0 and allowing spindle 36 to rotate. As soon as spindle 36 commences to rotate, cam 28 on sleeve 26 engages with the upper end of lever H, so preventing it from re-engaging with the detent Ill. The spindle 36 will therefore continue to rotate until the sleeve 26 has completed one revolution, when the upper'endof lever I! will -be released, so as to permit it to rotate, and 're-"eng'age with the detent H) on spindle 36, thus bringing it to rest. As spindle 36 rotates the cam 2| allows lever 6 to move to the left, thus'releasing the five selector levers 4, and allowing them to press against the cams on the sleeve 33 which are presented to them. The cams are cut 'so as to set the levers 4 under the action of their springs 2 in a manner corresponding to the letter to be transmitted. The movement of levers 4 control the setting of bars 3 andthus the operationof the transmitter. While levers '4 are being set cam l8 acts to release the start stop transmitter through the medium of lever I6 and bar ll. After the five signals havebeen transmitted those bars-3 which have 'been-movedto'the left are reset to theirright-hand positionsby lever 5'under the action of springs 1 controlled'by cam 20. The timing is such that the start stop transmitter is arrested before the lever I6 under the action ofcam l8, re'starts it to transmit another'character, andthe cycleof'operations just described is-repeated;

Under some circumstances it is necessary to prevent'the levers 4 and 5 from interfering with the setting of bars '3 during the first portion of the revolution of sleeve 33; 'for example, through an intervalequalto four letter characters. For this purposathe cams 29 and 30 are so cut that when levers 5 0r'6 are released by cams 20 and 2| their upwardly extending .portions will bear against the two cams 29 and 30 respectively, andwill be prevented from moving.

Whilethe answer back device is in operation it is important 'to prevent the keyboard of the transmitter from being operated in order to prevent mutilation of the signals being sent out by the answer back device. For this purpose the extension 9 on the lever H is adapted to maintain a bar'8 in engagement with the keyboard combination bars during the time the sleeve 26 is rotating. Thebar B prevents thecombinatio'n bars from 'beingmoved, and thus prevents any key on the keyboard frombeing depressed.

In order'thatthe cams 32 on the sleeve 33 may be readily changedthey are held in slots in the sleeve 33 by flanged discs 3| and 34 by meansof a nut 35. The collar -34has a single slot in it corresponding to one ofthe slots in the sleeve 33. Thus as the nut 35 is slacked the collar'34 may be turned so as ,t'o'bring the slot in it opposite to any-cam which may then be abstracted and replaced. The collar is finally turned into such a position that the slot in it does not come opposite any cam and the nut is then reclamped.

What is claimed is:

1. In type printing telegraph apparatus, a shaft, means for automatically releasing said shaft for rotation on receipt of a distinctive signal, a sleeve carrying cams cut to represent a set of characters to be transmitted, reduction gearing on said shaft for driving said sleeveat a reduced speed, a set of adjustable combination bars f or i determining "characters, means periodically contacting said cams for determining the adjustment of said "combination bars for the transmission of signals, a series of characters represented by said cams, "and means for maintaining said shaft in rotation until all said signals have been transmitted and for arresting said shaft thereafter.

2. Intype printing telegraph apparatus, a shaft, means for automatically releasing said shaft for rotation on receipt of a distinctive signal, a sleeve carrying cams 'cut to represent a set of characters'tobe'transmitted, means on said shaft for rotating said sleeve at a reduced speed, a set of pivoted levers, one for each element of a signal, means on said shaft for reciprocating said levers against said cams once for each character to be transmitted, 'means for determining the trans" mission of a signal for each character'represented bythesetting of said levers by said cams,'and means for maintaining said shaft in rotation until all said signals have been transmitted and for arresting said shaft thereafter.

3. In typeprinting telegraph apparatus, a set of combination bars, means for setting said bars in various combinations to represent characters for transmission, a cam shaft for transmitting a. start signal, followed by a series-of signals determinedby the setting of said combination bars, a shaft, means for releasing said shaft automatically on receipt of a distinctive signal, a sleeve carrying cams cut to represent a set of characters to be transmitted, reduction gearing for driving said sleeve from said shaft, means on said shaft for releasing said cam shaft for rotation for each character cut on said sleeve, and means on said shaft for setting said combination bars according to said cams on said sleeve.

'4. In type, printing telegraph apparatus, a set of combination bars, keyboard means for setting said combination bars in various combinations to represent characters for transmission, a cam shaft for transmitting a start signal followed by a series ofsignalsdetermined by the setting of said combination bars, a sleeve carrying cams cut to; represent a set-of characters to be transmitted, means'for automatically releasing said sleeve for rotation on receipt of a distinctive signal, means for reciprocating a set of pivoted levers, one for each combination-bar, against each set of cams representinga character to set said combination bars and means for releasing said cam shaft for rotation for each setting of said combination bars by said pivoted levers.

REGINALD DENNIS SALMON. FRANK REGINALD THOMAS. 

